Search for single character

I would like to search for strings like iPhone 1 or iPhone X. So, I entered "iPhone ?" to find them all, as the documentation says, that ? matches exactly one character. But it doesn’t work. I get no results. I have to enter "iPhone [a-z0-9]". However, this is just an example where I know that the single character is a letter or digit.

Additionally I would like to know, how to search for exact strings. "Johnson:" ignores the colon. Also searching for code like "<strong>" seems not to be possible. Is there an escape character for the characters which are used as search operators?

A wildcard that should match a word requires more specific information, e.g. only * or ? do not work. In your case searching for "iPhone [1-9X]" should finde all iPhones up to iPhone X.

Thanks for your fast answer. The Help should say explicitly, that they only work inside words.